[libcamera-devel] [PATCH 13/18] ipa: ipu3: Isolate ipa_context documentation

[Jean-Michel Hautbois]

Hi Kieran,

On 30/09/2021 12:59, Kieran Bingham wrote:
> Hi JM,
> 
> On 30/09/2021 10:55, Jean-Michel Hautbois wrote:
>> From: Kieran Bingham <kieran.bingham at ideasonboard.com>
>>
>> The IPU3 IPA core is growing with additional documentation. The
>> ipa_context documentation is stored here, but it pushes the IPU3
>> documentation and implementation further from the head of the file.
>>
>> Furthermore, the ipa_context documentation is outside of the ipa::ipu3
>> namespace and isn't identified correctly by Doxygen.
>>
>> Move the ipa_context to its own compilation object even though there
>> isn't any code, but to maintain consistency with our documentation
>> model.
>>
>> Correctly re-introduce the documentation into the libcamera::ipa::ipu3
>> namespace during the move.
>>
>> Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
>> ---
>>  src/ipa/ipu3/ipa_context.cpp | 113 +++++++++++++++++++++++++++++++++++
>>  src/ipa/ipu3/ipu3.cpp        | 104 --------------------------------
>>  src/ipa/ipu3/meson.build     |   1 +
>>  3 files changed, 114 insertions(+), 104 deletions(-)
>>  create mode 100644 src/ipa/ipu3/ipa_context.cpp
>>
>> diff --git a/src/ipa/ipu3/ipa_context.cpp b/src/ipa/ipu3/ipa_context.cpp
>> new file mode 100644
>> index 00000000..40d79772
>> --- /dev/null
>> +++ b/src/ipa/ipu3/ipa_context.cpp
>> @@ -0,0 +1,113 @@
>> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
>> +/*
>> + * Copyright (C) 2021, Google Inc.
>> + *
>> + * ipa_context.cpp - IPU3 IPA Context
>> + */
>> +
>> +#include "ipa_context.h"
>> +
>> +namespace libcamera::ipa::ipu3 {
>> +
>> +/**
>> + * \file ipa_context.h
>> + * \brief Context and state information shared between the algorithms
>> + */
>> +
>> +/**
>> + * \struct IPASessionConfiguration
>> + * \brief Session configuration for the IPA module
>> + *
>> + * The session configuration contains all IPA configuration parameters that
>> + * remain constant during the capture session, from IPA module start to stop.
>> + * It is typically set during the configure() operation of the IPA module, but
>> + * may also be updated in the start() operation.
>> + */
>> +
>> +/**
>> + * \struct IPAFrameContext
>> + * \brief Per-frame context for algorithms
>> + *
>> + * The frame context stores data specific to a single frame processed by the
>> + * IPA. Each frame processed by the IPA has a context associated with it,
>> + * accessible through the IPAContext structure.
>> + *
>> + * \todo Detail how to access contexts for a particular frame
>> + *
>> + * Each of the fields in the frame context belongs to either a specific
>> + * algorithm, or to the top-level IPA module. A field may be read by any
>> + * algorithm, but should only be written by its owner.
>> + */
>> +
>> +/**
>> + * \struct IPAContext
>> + * \brief Global IPA context data shared between all algorithms
>> + *
>> + * \var IPAContext::configuration
>> + * \brief The IPA session configuration, immutable during the session
>> + *
>> + * \var IPAContext::frameContext
>> + * \brief The frame context for the frame being processed
>> + *
>> + * \todo While the frame context is supposed to be per-frame, this
>> + * single frame context stores data related to both the current frame
>> + * and the previous frames, with fields being updated as the algorithms
>> + * are run. This needs to be turned into real per-frame data storage.
>> + */
>> +
>> +/**
>> + * \struct IPASessionConfiguration::grid
>> + * \brief Grid configuration of the IPA
>> + *
>> + * \var IPASessionConfiguration::grid::bdsGrid
>> + * \brief Bayer Down Scaler grid plane config used by the kernel
>> + *
>> + * \var IPASessionConfiguration::grid::bdsOutputSize
>> + * \brief BDS output size configured by the pipeline handler
>> + */
>> +
>> +/**
>> + * \struct IPAFrameContext::agc
>> + * \brief Context for the Automatic Gain Control algorithm
>> + *
>> + * The exposure and gain determined are expected to be applied to the sensor
>> + * at the earliest opportunity.
>> + *
>> + * \var IPAFrameContext::agc::exposure
>> + * \brief Exposure time expressed as a number of lines
>> + *
>> + * \var IPAFrameContext::agc::gain
>> + * \brief Analogue gain multiplier
>> + *
>> + * The gain should be adapted to the sensor specific gain code before applying.
>> + */
>> +
>> +/**
>> + * \struct IPAFrameContext::awb
>> + * \brief Context for the Automatic White Balance algorithm
>> + *
>> + * \struct IPAFrameContext::awb::gains
>> + * \brief White balance gains
>> + *
>> + * \var IPAFrameContext::awb::gains::red
>> + * \brief White balance gain for R channel
>> + *
>> + * \var IPAFrameContext::awb::gains::green
>> + * \brief White balance gain for G channel
>> + *
>> + * \var IPAFrameContext::awb::gains::blue
>> + * \brief White balance gain for B channel
>> + */
>> +
>> +/**
>> + * \struct IPAFrameContext::toneMapping
>> + * \brief Context for ToneMapping and Gamma control
>> + *
> 
> I think this now causes
> 
>  * \var IPAFrameContext::toneMapping::gamma
>  * \brief Gamma value for the LUT
> 
> to be dropped from here, and needs to be added in.
> 

Oh, I did not get a warning for it !!
Thanks !

> 
> 
>> + * \var IPAFrameContext::toneMapping::gammaCorrection
>> + * \brief Per-pixel tone mapping implemented as a LUT
>> + *
>> + * The LUT structure is defined by the IPU3 kernel interface. See
>> + * <linux/intel-ipu3.h> struct ipu3_uapi_gamma_corr_lut for further details.
>> + */
>> +
>> +} /* namespace libcamera::ipa::ipu3 */
>> diff --git a/src/ipa/ipu3/ipu3.cpp b/src/ipa/ipu3/ipu3.cpp
>> index 9867c993..1b1fc052 100644
>> --- a/src/ipa/ipu3/ipu3.cpp
>> +++ b/src/ipa/ipu3/ipu3.cpp
>> @@ -37,110 +37,6 @@
>>  #include "algorithms/tone_mapping.h"
>>  #include "libipa/camera_sensor_helper.h"
>>  
>> -/**
>> - * \file ipa_context.h
>> - * \brief Context and state information shared between the algorithms
>> - */
>> -
>> -/**
>> - * \struct IPASessionConfiguration
>> - * \brief Session configuration for the IPA module
>> - *
>> - * The session configuration contains all IPA configuration parameters that
>> - * remain constant during the capture session, from IPA module start to stop.
>> - * It is typically set during the configure() operation of the IPA module, but
>> - * may also be updated in the start() operation.
>> - */
>> -
>> -/**
>> - * \struct IPAFrameContext
>> - * \brief Per-frame context for algorithms
>> - *
>> - * The frame context stores data specific to a single frame processed by the
>> - * IPA. Each frame processed by the IPA has a context associated with it,
>> - * accessible through the IPAContext structure.
>> - *
>> - * \todo Detail how to access contexts for a particular frame
>> - *
>> - * Each of the fields in the frame context belongs to either a specific
>> - * algorithm, or to the top-level IPA module. A field may be read by any
>> - * algorithm, but should only be written by its owner.
>> - */
>> -
>> -/**
>> - * \struct IPAContext
>> - * \brief Global IPA context data shared between all algorithms
>> - *
>> - * \var IPAContext::configuration
>> - * \brief The IPA session configuration, immutable during the session
>> - *
>> - * \var IPAContext::frameContext
>> - * \brief The frame context for the frame being processed
>> - *
>> - * \todo While the frame context is supposed to be per-frame, this
>> - * single frame context stores data related to both the current frame
>> - * and the previous frames, with fields being updated as the algorithms
>> - * are run. This needs to be turned into real per-frame data storage.
>> - */
>> -
>> -/**
>> - * \struct IPASessionConfiguration::grid
>> - * \brief Grid configuration of the IPA
>> - *
>> - * \var IPASessionConfiguration::grid::bdsGrid
>> - * \brief Bayer Down Scaler grid plane config used by the kernel
>> - *
>> - * \var IPASessionConfiguration::grid::bdsOutputSize
>> - * \brief BDS output size configured by the pipeline handler
>> - */
>> -
>> -/**
>> - * \struct IPAFrameContext::agc
>> - * \brief Context for the Automatic Gain Control algorithm
>> - *
>> - * The exposure and gain determined are expected to be applied to the sensor
>> - * at the earliest opportunity.
>> - *
>> - * \var IPAFrameContext::agc::exposure
>> - * \brief Exposure time expressed as a number of lines
>> - *
>> - * \var IPAFrameContext::agc::gain
>> - * \brief Analogue gain multiplier
>> - *
>> - * The gain should be adapted to the sensor specific gain code before applying.
>> - */
>> -
>> -/**
>> - * \struct IPAFrameContext::awb
>> - * \brief Context for the Automatic White Balance algorithm
>> - *
>> - * \struct IPAFrameContext::awb::gains
>> - * \brief White balance gains
>> - *
>> - * \var IPAFrameContext::awb::gains::red
>> - * \brief White balance gain for R channel
>> - *
>> - * \var IPAFrameContext::awb::gains::green
>> - * \brief White balance gain for G channel
>> - *
>> - * \var IPAFrameContext::awb::gains::blue
>> - * \brief White balance gain for B channel
>> - */
>> -
>> -/**
>> - * \struct IPAFrameContext::toneMapping
>> - * \brief Context for ToneMapping and Gamma control
>> - *
>> - * \var IPAFrameContext::toneMapping::gamma
>> - * \brief Gamma value for the LUT
>> - *
>> - * \var IPAFrameContext::toneMapping::gammaCorrection
>> - * \brief Per-pixel tone mapping implemented as a LUT
>> - *
>> - * The LUT structure is defined by the IPU3 kernel interface. See
>> - * <linux/intel-ipu3.h> struct ipu3_uapi_gamma_corr_lut for further details.
>> - */
>> -
>>  /* Minimum grid width, expressed as a number of cells */
>>  static constexpr uint32_t kMinGridWidth = 16;
>>  /* Maximum grid width, expressed as a number of cells */
>> diff --git a/src/ipa/ipu3/meson.build b/src/ipa/ipu3/meson.build
>> index 39320980..3194111a 100644
>> --- a/src/ipa/ipu3/meson.build
>> +++ b/src/ipa/ipu3/meson.build
>> @@ -5,6 +5,7 @@ subdir('algorithms')
>>  ipa_name = 'ipa_ipu3'
>>  
>>  ipu3_ipa_sources = files([
>> +    'ipa_context.cpp',
>>      'ipu3.cpp',
>>  ])
>>  
>>